US20150093135A1 - Fixing apparatus and image forming apparatus including the same - Google Patents
Fixing apparatus and image forming apparatus including the same Download PDFInfo
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- US20150093135A1 US20150093135A1 US14/564,467 US201414564467A US2015093135A1 US 20150093135 A1 US20150093135 A1 US 20150093135A1 US 201414564467 A US201414564467 A US 201414564467A US 2015093135 A1 US2015093135 A1 US 2015093135A1
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- rotation
- fixing
- web sheet
- swing lever
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
- G03G15/2003—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat
- G03G15/2014—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using contact heat
- G03G15/2017—Structural details of the fixing unit in general, e.g. cooling means, heat shielding means
- G03G15/2025—Structural details of the fixing unit in general, e.g. cooling means, heat shielding means with special means for lubricating and/or cleaning the fixing unit, e.g. applying offset preventing fluid
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- General Physics & Mathematics (AREA)
- Fixing For Electrophotography (AREA)
Abstract
A fixing apparatus of the present invention includes a fixing rotation member, a rotation drive portion that rotates the fixing rotation member, a cleaning web sheet that cleans a circumferential surface of the fixing rotation member, a cleaning web sheet roller that takes up or feeds out the cleaning web sheet, a swing cam rotationally driven by the rotation drive portion, a rotation transmission portion that transmits a rotation drive force to the cleaning web sheet roller, a one way clutch provided on an input shaft of the rotation transmission portion, and a swing lever connected to the one way clutch and biased so as to be brought into slide contact with the swing cam.
Description
- This application is a Divisional of co-pending U.S. patent application Ser. No. 13/105,963 filed on May 12, 2011, and claims priority under 35 U.S.C. §119(a) on Patent Application No. 2010-111392 filed in Japan on May 13, 2010, and Patent Application No. 2010-111394 filed in Japan on May 13, 2010. All of the above applications are hereby expressly incorporated by reference into the present application.
- 1. Field of the Invention
- The present invention relates to a fixing apparatus that fixes a toner image formed on a recording sheet and an image forming apparatus including the same.
- 2. Description of the Related Art
- A fixing apparatus of this type is applied to an image forming apparatus that uses an electrophotographic method, an electrostatic recording method, a magnetic photographic method, or the like. Such a fixing apparatus heats and presses a recording sheet (such as plain paper, electrostatic recording paper, or photographic paper) onto which a toner image has been transferred, the recording sheet being sandwiched between a pair of fixing rotation members (belt, roller), and thereby fixes the toner image on the recording sheet.
- In such a fixing apparatus, the circumferential surface of a fixing rotation member may become smeared due to toner and the like, and thus it is necessary to clean the circumferential surface of the fixing rotation member using a blade, felt, a web sheet, or the like. Further, if the processing speed of the image forming apparatus is fast, and the number of sheets to be printed per unit time is large, smearing on the fixing rotation member of the fixing apparatus increases, and thus the smearing cannot be completely removed by cleaning the fixing rotation member using a blade or felt. Thus, cleaning using a web sheet is often adopted.
- For example, in the fixing apparatus disclosed in JP H8-185074A (hereinafter, referred to as Patent Document 1), a web sheet is fed out from a feed roller and taken up by a take-up roller, and the web sheet is pushed against a fixing roller during the feeding-out and taking-up operation, thereby cleaning the circumferential surface of the fixing roller. Further, the take-up roller is driven by a motor so as to rotate at a low speed, thereby taking up and feeding out the web sheet.
- In the fixing apparatus disclosed in JP H9-197884A (hereinafter, referred to as Patent Document 2), a web driving solenoid is used in order to drive a take-up roller that takes up a web sheet. Moreover, the amount by which the web sheet is taken up is adjusted according to image density.
- However, even if smearing on a fixing rotation member can be effectively removed by adopting cleaning using a web sheet, if a motor or a solenoid for rotating the web sheet take-up roller at a low speed is provided as with the case of the fixing apparatuses disclosed in
Patent Documents - On this account, it is conceivable to use a motor for rotating a fixing rotation member as a motor for rotating a web sheet take-up roller. In this case, the rotational speed of the web sheet take-up roller is very slow, compared with the rotational speed of the fixing rotation members, and thus a great speed reduction ratio will be necessary.
- However, for example, in a configuration in which the distance between the shafts of the fixing rotation members is changed according to the thickness of a recording sheet, the positional relationship among the shaft of the web sheet take-up roller and the shafts of fixing rotation members also changes. Thus, it was difficult to constitute a power transmission mechanism that can rotate both a fixing rotation member and the web sheet take-up roller using one motor, and can sufficiently increase the speed reduction ratio of the web sheet take-up roller.
- Further, in the case where the motor for rotating a fixing rotation member is used as a motor for rotating the web sheet take-up roller, it was difficult to adjust the amount by which the web sheet is taken up since the fixing rotation members and the web sheet take-up roller are caused to operate in conjunction with each other. For example, if the process speed is switched and set according to a color image or a monochrome image, the amount by which the web sheet is taken up also changed, and thus the take-up amount was not able to be accurately set.
- In view of this, a first object of the present invention is to provide a fixing apparatus that can cause fixing rotation members and a take-up roller for a web sheet to rotate at respectively appropriate rotational speeds using one drive source, and rotate the take-up roller for the web sheet and the fixing rotation members together even if the positional relationship among the shaft of the take-up roller for the web sheet and the shafts of the fixing rotation members changes, and an image forming apparatus including the same.
- Further, a second object of the present invention is to provide a fixing apparatus that can cause fixing rotation members and a take-up roller for a web sheet to rotate at respectively appropriate rotational speeds using one drive source, and adjust the amount by which the web sheet is taken up.
- In order to achieve the above first object, a fixing apparatus of the present invention includes a fixing rotation member, a rotation drive portion that rotates the fixing rotation member, a cleaning web sheet that cleans a circumferential surface of the fixing rotation member, a cleaning web sheet roller that takes up or feeds out the cleaning web sheet, a swing cam that is rotationally driven by the rotation drive portion, a rotation transmission portion that transmits a rotation drive force to the cleaning web sheet roller, a one way clutch that is provided on an input shaft of the rotation transmission portion, a swing lever that is connected to the one way clutch and biased so as to be brought into slide contact with the swing cam, and a separating portion that separates the swing lever from the swing cam, wherein if the swing cam is rotated by the rotation drive portion, the swing lever that is in slide contact with the swing cam repeatedly swings, the swinging of the swing lever is transmitted as an intermittent one-way rotation to the input shaft of the rotation transmission portion via the one way clutch, and the intermittent rotation is transmitted to the cleaning web sheet roller via the rotation transmission portion.
- In such a fixing apparatus of the present invention, rotation of the swing cam causes the swing lever to swing (reciprocatively rotate), the swinging of the swing lever is transmitted as an intermittent one-way rotation via the one way clutch, and thus a great speed reducing ratio can be obtained.
- Even if the positional relationship among the shaft of the cleaning web sheet roller on the rotation transmission portion side and the shafts of the fixing rotation members on the rotation drive portion side changes, which changes the positional relationship between the swing lever and the swing cam, as long as the swing lever is in slide contact with the swing cam, the swing lever swings following the rotation of the swing cam, and a rotation drive force is transmitted from the swing cam to the swing lever, thereby rotating the cleaning web sheet roller.
- If the swing lever is separated from the swing cam, the swinging of the swing lever stops, and thus the cleaning web sheet roller stops, which stops taking up and feeding out of the cleaning web sheet.
- Alternatively, a fixing apparatus of the present invention includes a first fixing rotation member and a second fixing rotation member that are pressed against each other, a rotation drive portion that rotates at least one of the first and second fixing rotation members, a cleaning web sheet that cleans a circumferential surface of the first or second fixing rotation member, a cleaning web sheet roller that takes up or feeds out the cleaning web sheet, a swing cam that is rotationally driven by the rotation drive portion, a rotation transmission portion that transmits a rotation drive force to the cleaning web sheet roller, a one way clutch that is provided on an input shaft of the rotation transmission portion, a swing lever that is connected to the one way clutch and biased so as to be brought into slide contact with the swing cam, a first frame that rotatably supports the first fixing rotation member, and a second frame that rotatably supports the second fixing rotation member, wherein the second frame is supported displaceably with respect to the first frame, enabling switching between a pressing state and a pressure canceled state of the first and second fixing rotation members, the first frame is provided with the swing cam, the second frame is provided with the swing lever, and the swing lever of the second frame is in slide contact with the swing cam of the first frame irrespective of a displacement position of the second frame, and if the swing cam is rotated by the rotation drive portion, the swing lever that is in slide contact with the swing cam repeatedly swings, the swinging of the swing lever is transmitted as an intermittent one-way rotation to the input shaft of the rotation transmission portion via the one way clutch, and the intermittent rotation is transmitted to the cleaning web sheet roller via the rotation transmission portion.
- In such a fixing apparatus of the present invention, by displacing the second frame with respect to the first frame, in other words, by displacing the shaft of the second fixing rotation member with respect to the shaft of the first fixing rotation member, switching between the pressing state and the pressure canceled state of the first and second fixing rotation members can be performed.
- In this case, the positional relationship between the swing lever and the swing cam also changes. If the swing lever is in slide contact with the swing cam, the swing lever swings following the rotation of the swing cam, and thus a rotation drive force is transmitted from the swing cam to the swing lever, which enables the cleaning web sheet roller to rotate.
- Further, the rotation of the swing cam causes the swing lever to the swing, and the swinging of the swing lever is transmitted as an intermittent one-way rotation via the one way clutch. Thus, a great speed reducing ratio can be obtained.
- Further, in the fixing apparatus of the present invention, the second frame may be provided with a separating portion that separates the swing lever from the swing cam.
- If the swing lever is separated from the swing cam, the swinging of the swing lever stops, and thus the cleaning web sheet roller stops, which stops taking up and feeding out of the cleaning web sheet.
- Moreover, in the fixing apparatus of the present invention, the second frame may be provided with the swing lever, the one way clutch, the rotation transmission portion, and the cleaning web sheet roller.
- In this case, the positions of the swing lever, the one way clutch, the rotation transmission portion, and the cleaning web sheet roller with respect to the first fixing rotation member are displaced together with the second fixing rotation member of the second frame.
- Further, an image forming apparatus of the present invention includes the above fixing apparatus of the present invention. In such an image forming apparatus, the same operation effects as those of the above fixing apparatus of the present invention are achieved.
- In order to achieve the above second object, another fixing apparatus of the present invention includes two fixing rotation members that are pressed against each other, a cleaning web sheet that cleans a circumferential surface of at least one of the fixing rotation members, a cleaning web sheet roller that takes up or feeds out the cleaning web sheet, a rotation drive portion that rotates at least one of the fixing rotation members, a swing cam that is rotationally driven by the rotation drive portion, a rotation transmission portion that transmits a rotation drive force to the cleaning web sheet roller, a one way clutch that is provided on an input shaft of the rotation transmission portion, a swing lever that is connected to the one way clutch and biased so as to be brought into slide contact with the swing cam, a separating portion that separates the swing lever from the swing cam, and a control portion that controls the separating portion, wherein if the swing cam is rotated by the rotation drive portion, the swing lever that is in slide contact with the swing cam repeatedly swings, the swinging of the swing lever is transmitted as an intermittent one-way rotation to the input shaft of the rotation transmission portion via the one way clutch, and the intermittent rotation is transmitted to the cleaning web sheet roller via the rotation transmission portion, and the control portion adjusts, by controlling the separating portion, a time period during which the swing lever is separated from the swing cam or a time period during which the swing lever is in slide contact with the swing cam.
- In such another fixing apparatus of the present invention, the rotation of the swing cam causes the swing lever to swing (reciprocatively rotate), and the swinging of the swing lever is transmitted as an intermittent one-way rotation via the one way clutch. Thus, a great speed reducing ratio can be obtained.
- Further, even if the positional relationship among the shaft of the cleaning web sheet roller on the rotation transmission portion side and the shafts of the fixing rotation members on the rotation drive portion side changes, which changes the positional relationship between the swing lever and the swing cam, as long as the swing lever is in slide contact with the swing cam, the swing lever swings following the rotation of the swing cam, and a rotation drive force is transmitted from the swing cam to the swing lever, thereby rotating the cleaning web sheet roller.
- Moreover, the time period during which the swing lever is separated from the swing cam or the time period during which the swing lever is in slide contact with the swing cam is adjusted by controlling the separating portion, and thus the amount by which the web sheet is taken up or fed out can be adjusted by changing the time period during which the cleaning web sheet roller is continued to rotate.
- Further, in the other fixing apparatus of the present invention, the control portion may change the time period during which the swing lever is separated from the swing cam or the time period during which the swing lever is in slide contact with the swing cam according to a rotational speed of the fixing rotation members.
- For example, the faster the rotational speed of the fixing rotation members is, the more the control portion may extend the time period during which the swing lever is separated from the swing cam or may shorten the time period during which the swing lever is in slide contact with the swing cam.
- Accordingly, irrespective of the rotational speed of the fixing rotation members, the amount by which the web sheet is taken up or fed out can be maintained substantially fixed.
- Moreover, the other fixing apparatus of the present invention may have a configuration in which switching between a pressing state and a pressure canceled state of the fixing rotation members is possible, the swing lever is in slide contact with the swing cam irrespective of the pressing state or the pressure canceled state, the swing lever that is in slide contact with the swing cam repeatedly swings if the swing cam is rotated by the rotation drive portion, the swinging of the swing lever is transmitted as an intermittent one-way rotation to the input shaft of the rotation transmission portion via the one way clutch, and the intermittent rotation is transmitted to the cleaning web sheet roller via the rotation transmission portion, and the control portion changes, depending on which of the pressing state and the pressure canceled state is switched to and set, a time period during which the swing lever is separated from the swing cam or a time period during which the swing lever is in slide contact with the swing cam.
- In this way, irrespective of the pressing state or the pressure canceled state, the amount by which the web sheet is taken up or fed out can be maintained substantially fixed.
- Further, in the other fixing apparatus of the present invention, the control portion may change the time period during which the swing lever is separated from the swing cam or the time period during which the swing lever is in slide contact with the swing cam, in accordance with a wound diameter of the cleaning web sheet roller.
- Accordingly, irrespective of the wound diameter of the cleaning web sheet roller, the amount by which the web sheet is taken up or fed out can be maintained substantially fixed.
- Moreover, in the other fixing apparatus of the present invention, the time period during which the swing lever is separated from the swing cam may be a time period with which the number of rotations of the swing cam becomes an integer.
- Accordingly, the rotation angle of the swing cam when the swing cam is stopped is fixed, and taking up of the web sheet is stopped when the swing lever reaches a fixed angle, which can suppress variations in the amount by which the web sheet is taken up.
- Next, the other image forming apparatus of the present invention includes the above other fixing apparatus of the present invention. In such an image forming apparatus, the same operation effects as those of the above fixing apparatus of the present invention are achieved.
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FIG. 1 is an explanatory diagram illustrating a schematic configuration of an image forming apparatus to which an embodiment of a fixing apparatus of the present invention is applied. -
FIG. 2 is a schematic cross-sectional view showing a schematic configuration of the fixing apparatus according to the embodiment of the present invention. -
FIG. 3 is a lateral view schematically showing the positional relationship between shafts of rollers in the fixing apparatus according to the embodiment of the present invention. -
FIG. 4 is a lateral view schematically showing gears of shafts of the rollers and a group of other gears in the fixing apparatus according to the embodiment of the present invention. -
FIG. 5 is a front view showing a schematic configuration of a rotation transmission unit in the fixing apparatus according to the embodiment of the present invention. -
FIG. 6A is a lateral view schematically showing a schematic configuration of a first frame, a first unit frame, and a second unit frame in a pressing state where a pressure roller and a fixing belt are pressed against each other in the fixing apparatus according to the embodiment of the present invention. -
FIG. 6B is a lateral view schematically showing a schematic configuration of the first frame, the first unit frame, and the second unit frame in a pressure canceled state where the pressure roller is in slight contact with the fixing belt in the fixing apparatus according to the embodiment of the present invention. -
FIG. 6C is a lateral view schematically showing a schematic configuration of the first frame, the first unit frame, and the second unit frame when the second unit frame has been detached from the first unit frame in the fixing apparatus according to the embodiment of the present invention. -
FIG. 7A is an explanatory diagram illustrating an operation of an eccentric cam and a swing lever in the pressing state where the pressure roller and the fixing belt are pressed against each other in the fixing apparatus according to the embodiment of the present invention. -
FIG. 7B is an explanatory diagram illustrating an operation of the eccentric cam and the swing lever in the pressing state where the pressure roller and the fixing belt are pressed against each other in the fixing apparatus according to the embodiment of the present invention. -
FIG. 7C is an explanatory diagram illustrating an operation of the eccentric cam and the swing lever in the pressing state where the pressure roller and the fixing belt are pressed against each other in the fixing apparatus according to the embodiment of the present invention. -
FIG. 7D is an explanatory diagram illustrating an operation of the eccentric cam and the swing lever in the pressing state where the pressure roller and the fixing belt are pressed against each other in the fixing apparatus according to the embodiment of the present invention. -
FIG. 8A is an explanatory diagram illustrating the swing angle of the swing lever in the pressing state where the pressure roller and the fixing belt are pressed against each other in the fixing apparatus according to the embodiment of the present invention. -
FIG. 8B is an explanatory diagram illustrating the swing angle of the swing lever in the pressure canceled state where the pressure roller is in slight contact with the fixing belt in the fixing apparatus according to the embodiment of the present invention. -
FIG. 9 is an explanatory diagram illustrating the state where the swing lever is separated from the eccentric cam in the fixing apparatus according to the embodiment of the present invention. -
FIG. 10 is a block diagram showing a schematic configuration of a control system of the fixing apparatus according to the embodiment of the present invention. -
FIG. 11 is a flowchart showing a procedure of correcting an operation time period of web sheet rollers in the fixing apparatus according to the embodiment of the present invention. - Below is a detailed description of an embodiment of the present invention, with reference to accompanying drawings.
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FIG. 1 is an explanatory diagram illustrating a schematic configuration of an image forming apparatus to which an embodiment of a fixing apparatus of the present invention is applied, and is a cross-sectional view showing an enlarged principal part of the image forming apparatus to which the embodiment of the fixing apparatus of the present invention is applied. Animage forming apparatus 1 is based on an electrophotographic method, and is provided with aphotosensitive drum 2, a transfer belt 3, a fixingapparatus 4, and the like. Thephotosensitive drum 2 has a photosensitive layer on the surface thereof, and is rotationally driven at a fixed rotational speed in the direction of arrow A inFIG. 1 . In accordance with the rotation of thephotosensitive drum 2, the surface of thephotosensitive drum 2 is uniformly charged to a predetermined potential by a charging apparatus (not shown) and is exposed by an exposing apparatus (not shown), an electrostatic latent image is thereby formed on that surface, and the electrostatic latent image on the surface of thephotosensitive drum 2 is developed so as to be a toner image by a development apparatus (not shown). - The transfer belt 3 is driven to revolve in the direction of arrow B in
FIG. 1 at the same speed as that of the surface speed of thephotosensitive drum 2, and a nip region is formed between the transfer belt 3 and thephotosensitive drum 2 by the transfer belt 3 being pressed by thephotosensitive drum 2. A recording sheet P transported from therebelow is led into this nip region. The toner image on the surface of thephotosensitive drum 2 is transferred onto the recording sheet P while the recording sheet P is being transported in this nip region. A high-voltage transfer bias (a high voltage of the opposite polarity (+) to the charge polarity (−) of the toner) is applied to the transfer belt 3. - The recording sheet P is transported upward, and led into the fixing
apparatus 4, where the toner image on the recording sheet P is fixed by being heated and pressed. The recording sheet P is transported further upward through atransport path 5, and is discharged onto a discharge tray (not shown) or the like. -
FIG. 2 is a cross-sectional view showing the fixingapparatus 4 according to the present embodiment. As shown inFIG. 2 , the fixingapparatus 4 is provided with a pressure roller 11 (second fixing rotation member), a hot roller 12 (first fixing rotation member), ahot assist roller 13, and an endless-shaped fixingbelt 14 extended between thehot roller 12 and thehot assist roller 13. Thepressure roller 11 and thehot roller 12 are pressed against each other via the fixingbelt 14, and a nip region N is formed between the fixingbelt 14 and thepressure roller 11. - The
pressure roller 11 is a roller having a three-layer structure in which an elastic layer is provided on the outer surface of a hollow shaft, and a releasing layer is formed on the outer surface of the elastic layer. A heater lamp (halogen lamp) serving as a heat source that heats thepressure roller 11 is provided inside the pressure roller 11 (inside the hollow shaft). - The
hot roller 12 is a roller in which an elastic layer is provided on the outer surface of a hollow shaft, and the elastic layer is sufficiently thick. - The fixing
belt 14 is an endless belt made of a material having favorable heat conduction, and has a releasing layer on its outer circumferential surface. - The
hot assist roller 13 is a roller in which a surface layer is provided on the outer surface of a hollow shaft, and a heater lamp (halogen lamp) serving as a heat source that heats thehot assist roller 13 is provided inside the hot assist roller 13 (inside the hollow shaft). - Here, since the elastic layer of the
hot roller 12 is sufficiently thick, the elastic layer of thehot roller 12 is greatly dented if thepressure roller 11 and thehot roller 12 are pressed against each other via the fixingbelt 14, thereby forming the wide nip region N between the fixingbelt 14 and thepressure roller 11. When therollers FIG. 2 , the fixingbelt 14 is caused to revolve via the nip region N while being heated by thehot assist roller 13. In this state, if a recording sheet is transported through the nip region N, the recording sheet is heated and pressed by the fixingbelt 14 and thepressure roller 11, thereby fixing a toner image on the recording sheet. - On the other hand, the fixing
apparatus 4 is provided with acleaning unit 6 that cleans the circumferential surface of thepressure roller 11. Thecleaning unit 6 is provided with a feed-out roller 22 (cleaning web sheet roller) having a web sheet 21 (cleaning web sheet) wound therearound, theweb sheet 21 being made of a thin fabric (having a thickness of about 100 μm) soaked with an oil (silicone oil), a take-uproller 23 to which the end of theweb sheet 21 is connected, a plurality oftension rollers 24 on which theweb sheet 21 that is fed out from the feed-outroller 22 and taken up by the take-up roller 23 (cleaning web sheet roller) is extended, and apressing roller 25 that presses theweb sheet 21 against thepressure roller 11 between the feed-outroller 22 and the take-uproller 23. Theweb sheet 21 is pressed against the surface of thepressure roller 11 by the pressingroller 25, which causes theweb sheet 21 to wipe off and remove adhering toner that has adhered to the surface of thepressure roller 11. - The
web sheet 21 is taken up little by little by the take-uproller 23 and is fed out little by little from the feed-outroller 22, according to the number of recording sheets to be printed, the print processing time period, or the amount of toner consumption. Accordingly, a portion of theweb sheet 21 in the nip region between thepressing roller 25 and thepressure roller 11 is renewed, thereby maintaining the cleaning capacity provided by theweb sheet 21. - In the fixing
apparatus 4 as described above, it is preferable to use a drive source of thepressure roller 11 and thehot roller 12 for fixing as a drive source for rotating the feed-outroller 22 and the take-uproller 23 for theweb sheet 21. In this case, the rotational speed of therollers web sheet 21 is very slow, compared with the rotational speed of therollers - As described in detail later, the distance between the shafts of the
rollers rollers rollers hot roller 12 and the shafts of therollers web sheet 21 also changes. However, it is necessary to rotate therollers rollers rollers rollers web sheet 21 in order to clean the circumferential surface of thepressure roller 11 at this time as well. - In view of this, in the present embodiment, the
rollers apparatus 4 are rotationally driven by a drive source (referred to as rotation drive portion in the present invention) of theimage forming apparatus 1, and by using aneccentric cam 36, aswing lever 37, and a one way clutch 41 that will be described later, the rotation of therollers rollers web sheet 21, and therollers rollers web sheet 21 are together rotated irrespective of the change in the distance between the shafts of therollers - In the case where the
rollers rollers web sheet 21 are caused to operate in conjunction with each other, if the rotational speed of therollers rollers web sheet 21 also changes. For example, the process speed may be changed depending on whether to print a color image or a monochrome image, and along with this, the rotational speed of therollers rollers eccentric cam 36, theswing lever 37, and the like changes, which also changes the rotational speed of therollers web sheet 21. - Then, if the rotational speed of the
rollers web sheet 21 changes in this way, the accurate amount by which theweb sheet 21 is taken up will no longer be maintained. Accordingly, the rotational speed of therollers web sheet 21 is controlled by enabling the switching between the operating and stopped states of therollers web sheet 21. - The following is a detailed description of a rotation drive mechanism using the
eccentric cam 36, theswing lever 37, and the one way clutch 41 as described above. -
FIG. 3 is a lateral view schematically showing the positional relationship among ashaft 11 a of thepressure roller 11, ashaft 12 a of thehot roller 12, ashaft 13 a of thehot assist roller 13, ashaft 22 a of the feed-outroller 22, ashaft 23 a of the take-uproller 23, thetension rollers 24, and ashaft 25 a of thepressing roller 25. -
FIG. 4 is a lateral view schematically showinggears shaft 11 a of thepressure roller 11, theshaft 12 a of thehot roller 12, theshaft 22 a of the feed-outroller 22, and theshaft 23 a of the take-uproller 23, and other gears that transmit rotation to thegears - Here, the drive source of the
rollers rollers web sheet 21 of the fixingapparatus 4 is provided on theimage forming apparatus 1 side, and when the fixingapparatus 4 is removably attached to theimage forming apparatus 1, a gear of an output shaft (not shown) that is rotationally driven on theimage forming apparatus 1 side meshes with aninput gear 31G of an input shaft of the fixingapparatus 4, thereby rotationally driving theinput gear 31G. - If the
input gear 31G is rotationally driven in the arrow direction (clockwise direction viewed from the side shown inFIG. 4 ), asmall gear 31 g fixed to theinput gear 31G is rotationally driven, and thegear 11G of thepressure roller 11 that meshes with thesmall gear 31 g rotates in the arrow direction (counter-clockwise direction viewed from the side shown inFIG. 4 ), thus causing thepressure roller 11 to rotate in the same direction as that of thegear 11G. - Further, if the
input gear 31G is rotationally driven in the arrow direction (clockwise direction viewed from the side shown inFIG. 4 ), agear 32G that meshes with theinput gear 31G and asmall gear 32 g fixed to thegear 32G rotate, and thegear 12G of thehot roller 12 that meshes with thesmall gear 32 g rotates in the arrow direction (clockwise direction viewed from the side shown inFIG. 4 ). A one way clutch (not shown) is interposed between thegear 12G and theshaft 12 a of thehot roller 12. As long as the rotation drive force of thepressure roller 11 is transmitted to thehot roller 12 via the fixingbelt 14, and thehot roller 12 idly rotates, rotation torque is not transmitted from thegear 12G to theshaft 12 a of thehot roller 12 via the one way clutch. Only when the rotational speed of thehot roller 12 decreases due to the slip of the fixingbelt 14 or thehot roller 12, the one way clutch is locked, and rotation torque is transmitted from thegear 12G to theshaft 12 a of thehot roller 12 via the one way clutch, thereby preventing the rotational delay of thehot roller 12. - The speed of the circumferential surface of the
pressure roller 11 and the speed of the circumferential surface of the fixingbelt 14 are set substantially the same, and a recording sheet is transported upward through the nip region N between thepressure roller 11 and the fixingbelt 14. - Moreover, a
gear 33G that meshes with thegear 32G and asmall gear 33 g fixed to thegear 33G rotate, agear 34G that meshes with thesmall gear 33 g rotates, acam gear 35G that meshes with thegear 34G rotates, and thus the eccentric cam (swing cam) 36 fixed to thecam gear 35G rotates in the arrow direction (clockwise direction viewed from the side shown inFIG. 4 ). - The
swing lever 37 is biased by aspring 38 in the counter-clockwise direction (counter-clockwise direction viewed from the side shown inFIG. 4 ) about ashaft 39, and is in contact with the circumferential surface of theeccentric cam 36. The first one way clutch 41 that transmits only the rotation of theswing lever 37 in the clockwise direction (clockwise direction viewed from the side shown inFIG. 4 ) to theshaft 39 is interposed between theswing lever 37 and theshaft 39. - Since the
swing lever 37 is in contact with theeccentric cam 36 by being biased by thespring 38, theswing lever 37 swings (reciprocatively rotates) as shown by arrow C when theeccentric cam 36 rotates. Following the swinging, only the rotation of theswing lever 37 in the clockwise direction is transmitted to theshaft 39 via the first one way clutch 41, and theshaft 39 intermittently rotates in the clockwise direction. For example, every time theeccentric cam 36 makes one full rotation, theshaft 39 rotates about 7.5° to 15°. A great speed reducing ratio can be obtained by the combination of theeccentric cam 36 and theswing lever 37. - The rotation of the
shaft 39 is further slowed down by a rotation transmission unit GU, and is transmitted to thegear 23G, thus causing the take-uproller 23 to rotate at a low speed in the arrow direction (counter-clockwise direction viewed from the side shown inFIG. 4 ). Accordingly, theweb sheet 21 is taken up little by little by the take-uproller 23, and thereby fed out little by little from the feed-outroller 22, thus causing the feed-outroller 22 to idly rotate. -
FIG. 5 is a front view schematically showing a schematic configuration of the rotation transmission unit GU. The rotation transmission unit GU uses theshaft 39 as a rotation input shaft. The first one way clutch 41 is provided at one end of theshaft 39, and theswing lever 37 is connected to the first oneway clutch 41. Specifically, the first one way clutch 41 is interposed between theswing lever 37 and the end of theshaft 39. Further, the other end of theshaft 39 is rotatably supported by a second one way clutch 42, and the second one way clutch 42 is fixed to a second unit frame of asecond frame 64 described later. - As described above, although only the rotation of the
swing lever 37 in the clockwise direction is transmitted to theshaft 39 via the first one way clutch 41, the second one way clutch 42 becomes free at this time, and theshaft 39 rotates in the clockwise direction. Although the first one way clutch 41 becomes free when theswing lever 37 rotates in the counter-clockwise direction and returns, the slight rotation torque in the counter-clockwise direction may be transmitted to theshaft 39 via the first one way clutch 41, which may cause theshaft 39 to rotate in the counter-clockwise direction, and thus rotation of theshaft 39 in the counter-clockwise direction is prohibited by the second oneway clutch 42. Accordingly, a combination of the first and second oneway clutches shaft 39 to reliably rotate intermittently in the clockwise direction. - The
shaft 39 is provided with fivegears small gear 44 g is fixed to theshaft 39, and rotates together with theshaft 39. Thegear 45G and thesmall gear 45 g are fixed to each other, and are supported so as to be rotatable about theshaft 39. Thegear 46G and thesmall gear 46 g are also fixed to each other, and are supported so as to be rotatable about theshaft 39. - The
shaft 23 a of the take-uproller 23 is also provided with fivegears gear 23G is fixed to theshaft 23 a of the take-uproller 23, and rotates together with theshaft 23 a of the take-uproller 23. Thegear 47G and thesmall gear 47 g are fixed to each other, and supported so as to be rotatable about theshaft 23 a. Thegear 48G and thesmall gear 48 g are also fixed to each other, and supported so as to be rotatable about theshaft 23 a. - The
gears shaft 39 respectively mesh with thegears shaft 23 a. If theshaft 39 rotates in the clockwise direction (clockwise direction viewed from the side shown inFIG. 4 ), thesmall gear 44 g fixed to theshaft 39 rotates, and this rotation is slowed down by being transmitted as follows: thegear 47G and thesmall gear 47 g→thegear 45G and thesmall gear 45 g→thegear 48G and thesmall gear 48 g→thegear 46G and thesmall gear 46 g→thegear 23G. Thegear 23G and theshaft 23 a fixed to thegear 23G rotate at a low speed, thus causing the take-uproller 23 also to rotate at a low speed in the arrow direction inFIG. 3 (counter-clockwise direction viewed from the side shown inFIG. 3 ). - Moreover, if the
gear 23G rotates, asmall gear 51 g that meshes with thegear 23G and agear 51G that is fixed to thesmall gear 51 g rotate. Then, a small gear (not shown) that meshes with thegear 51G and agear 52G that is fixed to that small gear rotate, and thus thegear 22G that meshes with thegear 52G rotates. Thegear 22G rotates together with a third one way clutch 43 in the arrow direction inFIG. 4 (clockwise direction viewed from the side shown inFIG. 4 ). - The third one way clutch 43 is interposed between the
gear 22G and theshaft 22 a of the feed-outroller 22, and freely rotates about theshaft 22 a of the feed-outroller 22 in the arrow direction inFIG. 4 (clockwise direction viewed from the side shown inFIG. 4 ). Accordingly, even if thegear 22G and the third one way clutch 43 rotate in the arrow direction inFIG. 4 (clockwise direction viewed from the side shown inFIG. 4 ), rotation torque in the arrow direction inFIG. 4 (clockwise direction viewed from the side shown inFIG. 4 ) is not transmitted from thegear 22G to theshaft 22 a of the feed-outroller 22 via the third one way clutch 43, and the feed-outroller 22 is not rotationally driven either. Accordingly, theweb sheet 21 is fed out from the feed-outroller 22 following theweb sheet 21 being taken up by the take-uproller 23, which causes the feed-outroller 22 to just rotate idly. - When the wound diameter of the
web sheet 21 on the take-uproller 23 increases, and the wound diameter of theweb sheet 21 on the feed-outroller 22 decreases, the take-up speed and the feed-out speed increases, and the idle rotation speed of the feed-outroller 22 increases, and thus the rotational speed is accelerated between theshaft 23 a of the take-uproller 23 and the third oneway clutch 43. Thus, even if the take-up speed and the feed-out speed increase, the third one way clutch 43 rotates faster, which maintains the idle rotation of the feed-outroller 22. - The third one way clutch 43 is provided in order to prevent the
web sheet 21 from being excessively fed out from the feed-outroller 22, by being locked when theweb sheet 21 is caught by thepressure roller 11, and the feed-outroller 22 idly rotates faster than the third one way clutch 43, for example. -
FIG. 6A is a lateral view schematically showing the schematic configuration of frames provided in the fixingapparatus 4. As shown inFIG. 6A , the fixingapparatus 4 has afirst frame 61 and thesecond frame 64. Further, thesecond frame 64 is constituted by afirst unit frame 62 and asecond unit frame 63. - In the
first frame 61, theshaft 12 a of thehot roller 12 and theshaft 13 a of thehot assist roller 13 are supported, and thegears FIG. 4 ), 32G, 32 g (shown inFIG. 4 ), 33G, 33 g (shown inFIG. 4 ), 34G, and 35G are rotatably supported. - In the
first unit frame 62 of thesecond frame 64, theshaft 11 a of thepressure roller 11 is supported. Thefirst unit frame 62 is coupled to thefirst frame 61 at the area of ashaft 31 a of theinput gear 31G, and can reciprocatively rotate about theshaft 31 a of theinput gear 31G as shown by arrow D inFIG. 6A . The reciprocative rotation angle thereof is about 3.5°. - The
second unit frame 63 of thesecond frame 64 is detachably fixed to the left wall part of thefirst unit frame 62. The rotation transmission unit GU is supported in thesecond unit frame 63. Specifically, thesecond unit frame 63 of thesecond frame 64 is provided with theswing lever 37, the rotation transmission unit GU, and therollers web sheet 21. - Here, normally, as shown in
FIG. 6A , thefirst unit frame 62 of thesecond frame 64 is biased by a spring (not shown) in the clockwise direction (clockwise direction viewed from the side shown inFIG. 6A ) about theshaft 31 a of theinput gear 31G. Thus, theshaft 11 a of thepressure roller 11 on thefirst unit frame 62 side comes close to theshaft 12 a of thehot roller 12 on thefirst frame 61 side, and thepressure roller 11 and thehot roller 12 are pressed against each other via the fixingbelt 14, thereby forming the nip region N between the fixingbelt 14 and thepressure roller 11. This state is the pressing state. - This pressing state is set when a recording sheet having a normal thickness is sandwiched in the nip region N between the fixing
belt 14 and thepressure roller 11, so as to fix a toner image on the recording sheet. - Further, as shown in
FIG. 6B , if thefirst unit frame 62 of thesecond frame 64 is rotated in the counter-clockwise direction (counter-clockwise direction viewed from the side shown inFIG. 6A ) about theshaft 31 a of theinput gear 31G, opposing the biasing force of the spring, theshaft 11 a of thepressure roller 11 on thefirst unit frame 62 side separates from theshaft 12 a of thehot roller 12 on thefirst frame 61 side, thereby causing thepressure roller 11 and the fixingbelt 14 to be in slight contact with each other. This state is the pressure canceled state. - In the pressure canceled state, not only the
shaft 11 a of thepressure roller 11 separates from theshaft 12 a of thehot roller 12, the position of theshaft 23 a of the take-uproller 23 with respect to theshaft 12 a of thehot roller 12 is also displaced. - This pressure canceled state is set when printing a thick envelope or the like. In the pressure canceled state, when a thick envelope or the like is sandwiched between the fixing
belt 14 and thepressure roller 11, a toner image on the envelope can be favorably fixed by applying appropriate pressure and heat to the envelope. - Further, the pressure canceled state is also set when not performing printing and fixing. In the pressing state, the
pressure roller 11 and thehot roller 12 are pressed against each other via the fixingbelt 14, which causes the elastic layer of thehot roller 12 to be greatly dented. Thus, if thehot roller 12 is left as it is for a long time, thehot roller 12 deforms, which causes a fixing defect. Accordingly, when not performing printing and fixing, the pressure canceled state is set, thereby preventing a dent from being generated in the elastic layer of thehot roller 12. - As is clear from
FIGS. 6A and 6B , to switch between the pressing state and the pressure canceled state, the second frame 64 (the first unit frame 62) only rotates about the shaft of theinput gear 31G. Thus, the distance between the shafts of theinput gear 31G and thegear 11G of thepressure roller 11 does not change due to this switching, thus maintaining the meshed state of theinput gear 31G and thegear 11G. Also, the distance between the shafts of theinput gear 31G and thegear 32G does not change either, thus maintaining the meshed state of theinput gear 31G and thegear 32G. Accordingly, regardless of whether the pressing state or the pressure canceled state is set, thepressure roller 11 and thehot roller 12 can be rotated, and fixing processing can be performed on a recording sheet or an envelope. - It should be noted that if the positional relationship between the
shaft 12 a of thehot roller 12 and theshaft 23 a of the take-uproller 23 changes due to the switching between the pressing state and the pressure canceled state, the positional relationship between theeccentric cam 36 and theswing lever 37 also changes. - However, even if either the pressing state or the pressure canceled state is set, the
swing lever 37 is biased by thespring 38 in the counter-clockwise direction about theshaft 39, and thereby brought into contact with the circumferential surface of theeccentric cam 36. Accordingly, regardless of whether the pressing state or the pressure canceled state is set, if theeccentric cam 36 rotates following the rotation of thepressure roller 11 and thehot roller 12, theswing lever 37 swings, and the take-uproller 23 and the feed-outroller 22 rotate at a low speed, which enables cleaning of the surface of thepressure roller 11 using theweb sheet 21. - Moreover, as shown in
FIG. 6C , thesecond unit frame 63 of thesecond frame 64 is removably attached to the left wall part of thefirst unit frame 62. Accordingly, it is possible to exchange thesecond unit frame 63. - The following is a detailed description of the operation of the
eccentric cam 36 and theswing lever 37.FIG. 7A is a lateral view schematically showing the peripheral mechanism of theeccentric cam 36 and theswing lever 37 in the pressing state in which thepressure roller 11 and thehot roller 12 are pressed against each other via the fixingbelt 14, as shown inFIG. 6A . - As shown in
FIG. 7A , the first one way clutch 41 is interposed between theswing lever 37 and theshaft 39, and theswing lever 37 is biased by thespring 38 about theshaft 39 in the counter-clockwise direction (counter-clockwise direction viewed from the side shown inFIG. 7A ), so as to be in contact with the circumferential surface of theeccentric cam 36. If theeccentric cam 36 rotates, theswing lever 37 swings (reciprocatively rotates) as shown by arrow C, and only the rotation of theswing lever 37 in the clockwise direction (clockwise direction viewed from the side shown inFIG. 7A ) is transmitted to theshaft 39 via the first oneway clutch 41. Thus, theshaft 39 rotates intermittently in the clockwise direction. - An L-shaped
control lever 71 is axially and rotatably supported by ashaft 71 a in thesecond unit frame 63 of the second frame 64 (seeFIG. 6A ). Apin 71 b is provided protruding at an end of thecontrol lever 71, and fitted inside aframe portion 37 a on the right side of the swing lever 37 (the opposite side to a side where the first one way clutch 41 is connected). Thepin 71 b of thecontrol lever 71 catches theframe portion 37 a, and accordingly the upward movement of theswing lever 37 is restricted by thepin 71 b of thecontrol lever 71. - A
fork portion 71 c is provided in the center of thecontrol lever 71, and if the tip of aplunger 72 is viewed from above, aconstricted portion 72 a of theplunger 72 is sandwiched inside thefork portion 71 c. Theplunger 72 is inserted in an opening in the center of asolenoid 73. When thesolenoid 73 is in a de-energized state, theplunger 72 is biased upward by aspring 74 so as to protrude from thesolenoid 73, whereas when thesolenoid 73 is in an energized state, theplunger 72 is pulled inside thesolenoid 73, opposing the biasing force of thespring 74. - If the
solenoid 73 is energized, thereby pulling theplunger 72 inside thesolenoid 73, thefork portion 71 c of thecontrol lever 71 that sandwiches theconstricted portion 72 a of theplunger 72 is pulled down. Consequently, thecontrol lever 71 rotates counter-clockwise about theshaft 71 a, and thepin 71 b of thecontrol lever 71 rises. Accordingly, theswing lever 37 can rotate in the counter-clockwise direction until theframe portion 37 a on the right side of theswing lever 37 bumps against thepin 71 b, which enables theswing lever 37 to swing. - At this time, the
swing lever 37 rotates counter-clockwise due to the biasing force of thespring 38, which brings theswing lever 37 to come into contact with the circumferential surface of theeccentric cam 36. Then, as shown inFIGS. 7A and 7B , if thecam gear 35G and theeccentric cam 36 rotate, theswing lever 37 follows the circumferential surface of theeccentric cam 36 so as to swing up and down. - In the pressing state in which the
pressure roller 11 and thehot roller 12 are pressed against each other via the fixingbelt 14 as shown inFIG. 6A , thepin 71 b of thecontrol lever 71 comes close to theeccentric cam 36 as shown inFIG. 8A , which widens the swing range of theswing lever 37 that is restricted by thepin 71 b. For example, in the present embodiment, the swing angle of theswing lever 37 is increased to 15°. - In the pressure canceled state as shown in
FIG. 6B , as shown inFIG. 8B , thepin 71 b of thecontrol lever 71 is separated from theeccentric cam 36, which narrows the swing range of theswing lever 37 that is restricted by thepin 71 b. For example, the swing angle of theswing lever 37 is decreased to 7.5° in the present embodiment. - In both the pressing state and the pressure canceled state, if the
cam gear 35G and theeccentric cam 36 rotate, theswing lever 37 follows the circumferential surface of theeccentric cam 36 so as to swing up and down, and thus theweb sheet 21 is taken up by the take-uproller 23, and fed out from the feed-out roller. - Further, in the pressing state, the
swing lever 37 swings 15° due to one full rotation of theeccentric cam 36, whereas in the pressure canceled state, theswing lever 37 swings 7.5° due to one full rotation of theeccentric cam 36. Thus, the rotational speed of the take-uproller 23 changes depending on whether the pressing state or the pressure canceled state is set. - As shown in
FIG. 9 , if thesolenoid 73 is de-energized so that theplunger 72 protrudes from thesolenoid 73, thefork portion 71 c of thecontrol lever 71 that sandwiches theconstricted portion 72 a of theplunger 72 is pushed up, and thecontrol lever 71 rotates clockwise about theshaft 71 a, which moves thepin 71 b of thecontrol lever 71 downward. At this time, thepin 71 b catches theframe portion 37 a on the right side of theswing lever 37, which pulls down the right side of theswing lever 37, and theswing lever 37 is thus rotated clockwise opposing the biasing force of thespring 38. Accordingly, theswing lever 37 is separated from the circumferential surface of theeccentric cam 36. Specifically, in the present embodiment, thesolenoid 73, theplunger 72, thecontrol lever 71, theshaft 71 a, and thepin 71 b constitute a separating portion that separates theswing lever 37 from the circumferential surface of theeccentric cam 36. - In the state where the
swing lever 37 is separated from the circumferential surface of theeccentric cam 36, the state where theswing lever 37 is stopped is maintained even if theeccentric cam 36 rotates. - Accordingly, the
swing lever 37 is brought into contact with or separated from the circumferential surface of theeccentric cam 36 by energizing or de-energizing thesolenoid 73, which enables theswing lever 37 to swing or the swinging thereof to be stopped. Consequently, therollers web sheet 21 can be rotated or the rotation of therollers web sheet 21 can be stopped. - For example, during a warm-up period when the
image forming apparatus 1 is turned on and a standby period thereof, even if therollers web sheet 21, and thus theswing lever 37 is separated from the circumferential surface of theeccentric cam 36, which stops the swinging of theswing lever 37, and the rotation of therollers web sheet 21 is thus stopped. - Further, the greater the number of recording sheets to be printed, the print processing time period, or the amount of toner consumption, the more a portion of the
web sheet 21 in the nip region between thepressing roller 25 and thepressure roller 11 becomes smeared. Thus, depending on the number of recording sheets to be printed, the print processing time period, and the amount of toner consumption, thesolenoid 73 is energized for a predetermined operating time period, theswing lever 37 is caused to swing, therollers web sheet 21 are rotated, and theweb sheet 21 is taken up and fed out. For example, every time the number of sheets to be printed is increased by 10, thesolenoid 73 is energized for a predetermined operating time period, theswing lever 37 is caused to swing, therollers web sheet 21 are rotated, and theweb sheet 21 is taken up by a fixed amount. - Moreover, when the wound diameter of the
web sheet 21 on the take-uproller 23 increases, and the speed to take up theweb sheet 21 by the take-uproller 23 is accelerated, the amount by which theweb sheet 21 is taken up and fed out becomes excessively large, and thus the operating time period of therollers web sheet 21 is shortened as appropriate (alternatively, a stop time period of theswing lever 37 is set, and taking up and feeding out of theweb sheet 21 are halted), thereby adjusting the amount by which theweb sheet 21 is taken up. - As described above, if the rotational speed of the
rollers web sheet 21 changes due to a change in the rotational speed of therollers roller 23 changes due to a change in the distance between the shafts of therollers rollers web sheet 21 changes, and thus the accurate amount by which theweb sheet 21 is taken up is no longer maintained. Accordingly, the amount by which theweb sheet 21 is taken up is adjusted by changing the operating time period (rotating time period) of therollers web sheet 21 as appropriate. - The following is a detailed description of the configuration for controlling the
swing lever 37 and therollers web sheet 21 to operate and stop. -
FIG. 10 is a block diagram showing a control system that performs such control. InFIG. 10 , acontrol portion 81 is mounted in the fixingapparatus 4, and controls the fixingapparatus 4. Thecontrol portion 81 brings theswing lever 37 into contact with the circumferential surface of theeccentric cam 36 or separates theswing lever 37 therefrom by energizing or de-energizing thesolenoid 73, for example. - A main control portion (not shown) on the
image forming apparatus 1 side gives a power-on warm-up or standby setting instruction to thecontrol portion 81. Under such a setting, the de-energizing state of thesolenoid 73 is maintained, so that theswing lever 37 is separated from the circumferential surface of theeccentric cam 36, which stops the swinging of theswing lever 37, and stops the rotation of therollers web sheet 21. Accordingly, wasteful taking up and feeding out of theweb sheet 21 are suppressed. - The
control portion 81 obtains the number of recording sheets to be printed, a print processing time period, the amount of toner consumption, and the like from the main control portion (not shown) on theimage forming apparatus 1 side, sets a predetermined operating time period based on these, and energizes thesolenoid 73 for this predetermined operating time period. This causes theswing lever 37 to come into contact with the circumferential surface of theeccentric cam 36 and theswing lever 37 to swing, thereby rotating therollers web sheet 21. Consequently, theweb sheet 21 is taken up and fed out. For example, every time the number of sheets to be printed is increased by 10, thesolenoid 73 is energized for an operating time period T, which causes theswing lever 37 to swing, and therollers web sheet 21 are thus rotated. As a result, theweb sheet 21 is taken up by a substantially fixed amount. - The
control portion 81 adds the operating time periods T of therollers web sheet 21 so as to obtain a cumulative total operating time period, and obtains a total amount by which theweb sheet 21 is taken up and that corresponds to this cumulative total operating time period. Thecontrol portion 81 obtains the wound diameter of theweb sheet 21 on the take-uproller 23 based on this total take-up amount, and an increase in the speed at which theweb sheet 21 is taken up based on this wound diameter, and corrects and shortens the operating time period T according to this speed increase. Actually, a table is stored in advance in which the cumulative total operating time period of therollers web sheet 21 and a coefficient α (<1) are associated with each other, and the coefficient α corresponding to this cumulative total operating time period is obtained with reference to this table. Then, a value calculated by multiplying the obtained coefficient α by the operating time period T is assumed to be the corrected operating time period T. Accordingly, even if the wound diameter of theweb sheet 21 on the take-uproller 23 increases, the amount by which theweb sheet 21 is taken up during the operating time period T is maintained fixed. - Further, when performing print processing, the
control portion 81 obtains, from the main control portion (not shown) on theimage forming apparatus 1 side, the process speed (rotational speed of therollers web sheet 21 is taken up by maintaining the number of rotations of therollers web sheet 21 during the operating time period T substantially fixed. - Especially, in the fixing
apparatus 4 according to the present embodiment, therollers rollers web sheet 21 are caused to operate in conjunction with each other using theeccentric cam 36, theswing lever 37, and the oneway clutch 41. Thus, the rotational speed of therollers web sheet 21 changes, depending on the process speed (rotational speed of therollers web sheet 21 is taken up by suppressing the change in the number of rotations of therollers web sheet 21 during the operating time period T, by correcting the operating time period T in such a way. - The following is a description of a procedure for correcting the operating time period T of the
rollers web sheet 21, with reference to the flowchart inFIG. 11 . - First, as described above, the
control portion 81 adds up the operating time periods of therollers web sheet 21, and obtains the cumulative total operating time period. Next, thecontrol portion 81 obtains the coefficient α corresponding to that cumulative total operating time period with reference to the table in which the cumulative total operating time period of therollers web sheet 21 and the coefficient α (<1) are associated with each other. Then, a value calculated by multiplying the obtained coefficient α by the fixed operating time period T is assumed to be the corrected operating time period T (step S101). - Subsequently, the
control portion 81 obtains either a first process speed V1 or a second process speed V2 from the main control portion (not shown) on theimage forming apparatus 1 side (step S102). For example, the first process speed V1 is assumed to be a process speed when printing a monochrome image. Further, the second process speed V2 is assumed to be a process speed when printing a color image, and the first process speed V1 is assumed to be set faster than the second process speed V2 (V1>V2). - Generally, there are many cases where the first process speed V1 is set, and thus the operating time period T obtained in step S101 is a time period for operating at the first process speed V1. Accordingly, if the
control portion 81 obtains the first process speed V1 (“V1” in step S102), thecontrol portion 81 transitions to step S104 without correcting the operating time period T. - Further, if the
control portion 81 obtains the second process speed V2 (“V2” in step S102), thecontrol portion 81 obtains a value (T·V1/V2) calculated by multiplying the operating time period T obtained in step S101 by V1/V2, and sets this value as the corrected operating time period T (step S103). - When the second process speed V2 is set, the rotational speed of the
rollers rollers web sheet 21 also decreases following this, and thus the amount by which theweb sheet 21 is taken up per unit time decreases. However, the operating time period T is corrected so as to be longer by being multiplied by V1/V2, which suppresses a change in the number of rotations of therollers web sheet 21 during the operating time period T, and the amount by which theweb sheet 21 is taken up is thereby maintained substantially fixed. - Next, the
control portion 81 obtains information indicating whether the pressing state or the pressure canceled state is set from the main control portion (not shown) on theimage forming apparatus 1 side (step S104). - Normally, the pressing state is set, and thus the operating time period T obtained in step S101 or S103 is a time period for operating in the pressing state. Accordingly, if the
control portion 81 obtains information indicating that the pressing state has been set (“pressing” in step S104), thecontrol portion 81 does not correct the operating time period T, and transitions to step S105. - Further, if the
control portion 81 obtains information indicating that the pressure canceled state has been set (“pressure canceled” in step S104), thecontrol portion 81 obtains a value calculated by multiplying a value calculated by dividing a swing angle θ1 of theswing lever 37 in the pressing state by a swing angle θ2 of theswing lever 37 in the pressure canceled state by the operating time period T obtained in step S101 or S103 (in other words, T·θ1/θ2), and sets this value as the corrected operating time period T (step S105). As shown inFIGS. 8A and 8B , the swing angle θ1 of theswing lever 37 in the pressing state is 15°, the swing angle θ2 of theswing lever 37 in the pressure canceled state is 7.5°, and thus the operating time period T in the pressure canceled state is twice as long as the operating time period T obtained in step S101 or S103. - When the pressure canceled state is set, compared with the time when the pressing state is set, the swing angle of the
swing lever 37 is halved, and the rotational speed of therollers web sheet 21 is also halved. However, since the operating time period T has been corrected so as to be doubled, a change in the number of rotations of therollers web sheet 21 during the operating time period T is suppressed, and the amount by which theweb sheet 21 is taken up is maintained substantially fixed. - Moreover, if the first process speed V1 is set, the operating time period T obtained in step S101 or S105 is corrected to a time period that is longer than or equal to the operating time period T and closest to the operating time period T and that corresponds to an integral multiple of a time period necessary for the
eccentric cam 36 to make one full rotation at the first process speed V1, and the operating time period T is determined (step S106). - Alternatively, in the case where the second process speed V2 is set, assuming that t2 is a time period necessary for the
eccentric cam 36 to make one full rotation at the second process speed V2, the operating time period T obtained in step S103 or S105 is corrected to a time period that is longer than or equal to the operating time period T and closest to the operating time period T, and that corresponds to an integral multiple of the time t2, and the operating time period T is determined (step S106). - Accordingly, the rotation angle of the
eccentric cam 36 while theeccentric cam 36 is stopped is fixed, the taking up of theweb sheet 21 is stopped when the angle of theswing lever 37 has reached a fixed angle, and thus variations in the amount by which theweb sheet 21 is taken up are suppressed. - The correction of the operating time period T ends in this way, and thereafter the
control portion 81 energizes thesolenoid 73 for the operating time period T so as to swing theswing lever 37, and thus rotates therollers web sheet 21, thereby taking up theweb sheet 21 by a fixed amount. - Such derivation of the operating time period T and rotation of the
rollers web sheet 21 during the operating time period T are performed every time the number of sheets to be printed is increased by 10, and theweb sheet 21 is taken up by a fixed amount each time. - Thus, in the fixing
apparatus 4 according to the present embodiment, the rotation of theeccentric cam 36 causes theswing lever 37 to swing, the swinging of theswing lever 37 becomes intermittent rotation in one way and transmitted via the first one way clutch 41, and thus a great speed reducing ratio can be obtained. - In both the pressure canceled state and the pressing state (specifically, even if the position of the
second frame 64 relative to thefirst frame 61 is displaced, the position of theshaft 23 a of the take-uproller 23 relative to theshaft 12 a of thehot roller 12 is thereby displaced, and thus the positional relationship between theeccentric cam 36 and theswing lever 37 changes), since theswing lever 37 is in slide contact with theeccentric cam 36, theswing lever 37 swings following the rotation of theeccentric cam 36, and a rotation drive force is transmitted from theeccentric cam 36 to theswing lever 37, thereby enabling the take-uproller 23 to rotate. - Moreover, according to the process speed (rotational speed of the
rollers rollers web sheet 21 changes, the appropriate amount by which theweb sheet 21 is taken up can be maintained by suppressing a change in the number of rotations of therollers rollers - Note that although the
pressure roller 11 and thehot roller 12 are pressed against each other via the fixingbelt 14 in the above embodiment, the present invention is also applicable to a configuration in which the pressure roller (fixing rotation member) 11 and the hot roller (fixing rotation member) 12 are directly pressed against each other. - The present invention may be embodied in various other forms without departing from the gist or essential characteristics thereof. Therefore, the embodiments disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All variations and modifications that come within the meaning and range of equivalency of the claims are intended to be embraced therein.
-
- 1 Image forming apparatus
- 2 Photosensitive drum
- 3 Transfer belt
- 4 Fixing apparatus
- 11 Pressure roller (Second fixing rotation member)
- 12 Hot roller (First fixing rotation member)
- 13 Hot assist roller
- 14 Fixing belt
- 21 Web sheet (Cleaning web sheet)
- 22 Feed-out roller (Cleaning web sheet roller)
- 23 Take-up roller (Cleaning web sheet roller)
- 24 Tension roller
- 25 Pressing roller
- 36 Eccentric cam
- 37 Swing lever
- 38 Spring
- 41 First one way clutch
- 42 Second one way clutch
- 43 Third one way clutch
- 61 First frame
- 62 First unit frame
- 63 Second unit frame
- 64 Second frame
- 71 Control lever
- 72 Plunger
- 73 Solenoid
- 74 Spring
- 81 Control portion
- GU Rotation transmission unit
Claims (13)
1. A fixing apparatus, comprising:
a fixing rotation member;
a first drive portion that rotates the fixing rotation member;
a cleaning web sheet that cleans a circumferential surface of the fixing rotation member;
a cleaning web sheet roller that takes up or feeds out the cleaning web sheet;
a rotation transmission portion that transmits a rotation drive force to the cleaning web sheet roller;
a second drive portion having a one way clutch that is provided on an input shaft of the rotation transmission portion;
a swing lever that is biased so as to be brought into slide contact with the second drive portion; and
a switching portion that switches between a first state in which the swing lever swings and a second state in which the swing lever does not swing,
wherein the swing lever that is in slide contact with the second drive portion repeatedly swings, the swinging of the swing lever is transmitted as an intermittent one-way rotation to the input shaft of the rotation transmission portion via the second drive portion, and the intermittent rotation is transmitted to the cleaning web sheet roller via the rotation transmission portion.
2. A fixing apparatus, comprising:
a first fixing rotation member and a second fixing rotation member that are pressed against each other;
a first drive portion that rotates at least one of the first and second fixing rotation members;
a cleaning web sheet that cleans a circumferential surface of the first or second fixing rotation member;
a cleaning web sheet roller that takes up or feeds out the cleaning web sheet;
a rotation transmission portion that transmits a rotation drive force to the cleaning web sheet roller;
a second drive portion having a one way clutch that is provided on an input shaft of the rotation transmission portion;
a swing lever that is biased so as to be brought into slide contact with the second drive portion;
a first frame that rotatably supports the first fixing rotation member; and
a second frame that rotatably supports the second fixing rotation member,
wherein the second frame is supported displaceably with respect to the first frame, enabling switching between a pressing state and a pressure canceled state of the first and second fixing rotation members, the first frame is provided with the second drive portion, the second frame is provided with the swing lever, and the swing lever of the second frame is in slide contact with the second drive portion of the first frame when the second frame is attached to the first frame, and
the swing lever that is in slide contact with the second drive portion repeatedly swings, the swinging of the swing lever is transmitted as an intermittent one-way rotation to the input shaft of the rotation transmission portion via the second drive portion, and the intermittent rotation is transmitted to the cleaning web sheet roller via the rotation transmission portion.
3. The fixing apparatus according to claim 2 , further comprising:
a switching portion that switches between a first state in which the swing lever swings and a second state in which the swing lever does not swing.
4. The fixing apparatus according to claim 2 ,
wherein the second frame is provided with the swing lever, the one way clutch, the rotation transmission portion, and the cleaning web sheet roller.
5. An image forming apparatus comprising the fixing apparatus according to claim 1 .
6. An image forming apparatus comprising the fixing apparatus according to claim 2 .
7. A fixing apparatus, comprising:
two fixing rotation members that are pressed against each other;
a cleaning web sheet that cleans a circumferential surface of at least one of the fixing rotation members;
a cleaning web sheet roller that takes up or feeds out the cleaning web sheet;
a first drive portion that rotates at least one of the fixing rotation members;
a rotation transmission portion that transmits a rotation drive force to the cleaning web sheet roller;
a second drive portion having a one way clutch that is provided on an input shaft of the rotation transmission portion;
a swing lever that is biased so as to be brought into slide contact with the second drive portion;
a switching portion that switches between a first state in which the swing lever swings and a second state in which the swing lever does not swing, and
a control portion that controls the switching portion,
wherein the swing lever that is in slide contact with the second drive portion repeatedly swings, the swinging of the swing lever is transmitted as an intermittent one-way rotation to the input shaft of the rotation transmission portion via the second drive portion, and the intermittent rotation is transmitted to the cleaning web sheet roller via the rotation transmission portion, and
the control portion adjusts, by controlling the switching portion, a time period in the second state or a time period in the first state.
8. The fixing apparatus according to claim 7 ,
wherein the control portion changes the time period in the second state or the time period in the first state according to a rotational speed of the fixing rotation members.
9. The fixing apparatus according to claim 8 ,
wherein the faster the rotational speed of the fixing rotation members is, the more the control portion extends the time period in the second state or shortens the time period in the first state.
10. The fixing apparatus according to claim 7 ,
wherein switching between a pressing state and a pressure canceled state of the fixing rotation members is possible, the swing lever is in slide contact with the second drive portion irrespective of the pressing state or the pressure canceled state, the swing lever that is in slide contact with the second drive portion repeatedly swings, the swinging of the swing lever is transmitted as an intermittent one-way rotation to the input shaft of the rotation transmission portion via the second drive portion, and the intermittent rotation is transmitted to the cleaning web sheet roller via the rotation transmission portion, and
the control portion changes, depending on which of the pressing state and the pressure canceled state is switched to and set, a time period in the second state or a time period in the first state.
11. The fixing apparatus according to claim 7 ,
wherein the control portion changes the time period in the second state or the time period in the first state, in accordance with a wound diameter of the cleaning web sheet roller.
12. The fixing apparatus according to claim 7 ,
wherein the time period in the second state is a time period with which the number of rotations of the second drive portion becomes an integer.
13. An image forming apparatus comprising the fixing apparatus according to claim 7 .
Priority Applications (1)
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US14/564,467 US9164434B2 (en) | 2010-05-13 | 2014-12-09 | Fixing apparatus and image forming apparatus including the same |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
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JP2010-111392 | 2010-05-13 | ||
JP2010-111394 | 2010-05-13 | ||
JP2010111394A JP5121880B2 (en) | 2010-05-13 | 2010-05-13 | Fixing device and image forming apparatus including the same |
JP2010111392A JP5121879B2 (en) | 2010-05-13 | 2010-05-13 | Fixing device and image forming apparatus including the same |
US13/105,963 US8948670B2 (en) | 2010-05-13 | 2011-05-12 | Fixing apparatus and image forming apparatus including the same |
US14/564,467 US9164434B2 (en) | 2010-05-13 | 2014-12-09 | Fixing apparatus and image forming apparatus including the same |
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US13/105,963 Division US8948670B2 (en) | 2010-05-13 | 2011-05-12 | Fixing apparatus and image forming apparatus including the same |
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US20150093135A1 true US20150093135A1 (en) | 2015-04-02 |
US9164434B2 US9164434B2 (en) | 2015-10-20 |
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US13/105,963 Active 2033-08-23 US8948670B2 (en) | 2010-05-13 | 2011-05-12 | Fixing apparatus and image forming apparatus including the same |
US14/564,467 Active US9164434B2 (en) | 2010-05-13 | 2014-12-09 | Fixing apparatus and image forming apparatus including the same |
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US13/105,963 Active 2033-08-23 US8948670B2 (en) | 2010-05-13 | 2011-05-12 | Fixing apparatus and image forming apparatus including the same |
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CN (2) | CN102243464B (en) |
Cited By (1)
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US20160306304A1 (en) * | 2015-04-17 | 2016-10-20 | Ricoh Company, Ltd. | Fixing device and image forming apparatus incorporating same |
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JP2012103447A (en) * | 2010-11-09 | 2012-05-31 | Fuji Xerox Co Ltd | Heating and pressing device and image forming apparatus |
US9740148B2 (en) * | 2012-07-27 | 2017-08-22 | Lexmark International, Inc. | Method and system for controlling a fuser assembly |
US9354568B2 (en) * | 2012-07-27 | 2016-05-31 | Lexmark International, Inc. | Method and system for controlling a fuser assembly using temperature feedback |
US9696672B2 (en) * | 2015-04-20 | 2017-07-04 | Ricoh Company, Ltd. | Drive transmission unit, fixing device with drive transmission unit, and image forming apparatus having fixing device with drive transmission unit |
JP7057886B2 (en) * | 2017-07-11 | 2022-04-21 | 株式会社リコー | Sheet transfer device, fixing device and image forming device |
EP3745208B1 (en) * | 2019-05-30 | 2022-11-16 | KYOCERA Document Solutions Inc. | Image forming apparatus provided with cleaning device |
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JPS5948783A (en) | 1982-09-13 | 1984-03-21 | Canon Inc | Cleaning device |
JPH02280181A (en) | 1989-04-20 | 1990-11-16 | Konica Corp | Cleaning device for fixing device |
JPH08185074A (en) | 1994-12-28 | 1996-07-16 | Canon Inc | Fixing device |
JPH09197884A (en) | 1996-01-12 | 1997-07-31 | Canon Inc | Cleaner, fixing device, and image forming device |
JP3451867B2 (en) * | 1997-01-08 | 2003-09-29 | 富士ゼロックス株式会社 | Fixing unit and image forming apparatus |
JPH11344105A (en) | 1998-05-29 | 1999-12-14 | Canon Inc | Presurizing mechanism for unit device |
JP4130743B2 (en) * | 2002-03-08 | 2008-08-06 | パナソニック コミュニケーションズ株式会社 | Fixing apparatus, image recording apparatus using the same, and multifunction machine |
JP4028423B2 (en) * | 2003-03-31 | 2007-12-26 | 京セラミタ株式会社 | Fixing apparatus and image forming apparatus |
JP2008145718A (en) | 2006-12-08 | 2008-06-26 | Ricoh Co Ltd | Driving device and image forming apparatus |
JP5552732B2 (en) * | 2008-03-31 | 2014-07-16 | 株式会社リコー | Fixing apparatus and image forming apparatus |
JP4633153B2 (en) | 2008-08-20 | 2011-02-16 | シャープ株式会社 | Fixing apparatus and image forming apparatus having the same |
-
2011
- 2011-05-12 CN CN201110126180.4A patent/CN102243464B/en active Active
- 2011-05-12 US US13/105,963 patent/US8948670B2/en active Active
- 2011-05-12 CN CN201510324198.3A patent/CN104898391A/en active Pending
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- 2014-12-09 US US14/564,467 patent/US9164434B2/en active Active
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US20160306304A1 (en) * | 2015-04-17 | 2016-10-20 | Ricoh Company, Ltd. | Fixing device and image forming apparatus incorporating same |
Also Published As
Publication number | Publication date |
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US8948670B2 (en) | 2015-02-03 |
CN104898391A (en) | 2015-09-09 |
CN102243464B (en) | 2015-07-15 |
US20110280636A1 (en) | 2011-11-17 |
CN102243464A (en) | 2011-11-16 |
US9164434B2 (en) | 2015-10-20 |
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